Today marks 100 years since the birth of Jane Jacobs. Her peerless first book, The Death and Life of Great American Cities, was published in 1961, at the height of a mistaken faith in the ‘modern’ city envisioned by utopian planners. But while Death and Life undermined that faith, it did not end it. The Jacobs centennial is an appropriate time to revisit her observations to glean lessons for going forward.

I stress “observations” because Jacobs was not ideological, nor prescriptive. She loved New York City’s Greenwich Village and successfully fought its demolition and redevelopment. It was her laboratory. But critics to the contrary, she did not advocate low-rise neighborhoods as the answer for every single place. She did not unilaterally oppose big buildings—only when they threatened to overshadow and weaken a viable urban fabric. She did not oppose big projects like mass transit, vast water works and citywide parks systems. She did not oppose roads “as long as the city is not reshaped to accommodate them,” she once told me. And she did not oppose infill redevelopment of urban areas as long as it was beneficial and appropriately scaled.

Instead, Jacobs promoted what worked, not what theory or ‘visions’ promised would work. And her wisdom was derived first and foremost from observation.

Early in her writing career, primarily as an architectural critic for Architecture Forum, Jacobs fell under the spell of the big, post-war building ideas that promised a new and better city once the old one was swept away.

Then, she observed the consequences and recanted. In Death and Life and six subsequent books, she took note of what worked and didn’t work. She recognized a parallel to the ecology of cities in the complex ecology of nature. She saw that parks designed as landscapes, rather than for actual users, stood empty. She saw how shopping streets with more going on than retail attracted more of the shoppers retail needs to flourish.

In the preface of Death and Life, she wrote: “The scenes that illustrate this book are all about us. For illustrations, please look closely at real cities.”

Real American cities today have become the go-to place for the young, the old and the tourist. This is especially true of the cities that did not hollow out their economic and cultural centers or traditional sidewalk-rich neighborhoods during the demolition derby days of Urban Renewal.

Her wisdom was derived first and foremost from observation.

If Jane Jacobs were with us today, she would have every right to say: I told you so.

Observation teaches us that the pre-World War II American city, still distinguished by its economic and social diversity, pedestrian-friendly and transit dependent character, can endure and thrive if it’s allowed to evolve with contemporary additions that don’t erase its fundamental strengths.

Historic neighborhoods—and not just those officially designated as landmarks—are experiencing extreme popularity, and most often the highest property values. Emerging entrepreneurs are choosing loft and commercial neighborhoods for start-ups, and slowly reviving production-based urban economies. Young residents are embracing a bicycle and mass transit lifestyle.

In contrast, the single-use “centers,” especially shopping malls, don’t seem to survive their 30-year mortgages without a major overhaul. Car-based cities struggle to create ‘walkable’ town centers. Many first rung suburbs are being vacated by residents who either move farther out, or return to downtown living. Who’s taking their place? Lower income residents, often immigrants, and small businesses priced out of the increasingly popular city.

This is not to say that all cities have regained lost vigor or even turned the corner on decline. America’s cities have been shrinking since the post-World War II love affair with the suburb. But where smart policies have taken root, where the evolving reversal is recognized and appropriately abetted, the organic urban rebirth slowly takes hold and expands.

Again, Jane Jacobs told us so.

The author and activist Jane Jacobs in 1962. (AP Photo/File)

Her wake-up call, as she writes in Death and Life, came in the mid-1950s during a visit to East Harlem. New, high-rise public housing surrounded by pretty but functionless lawns had erased the formerly dense mix of retail, institutional and residential uses. She learned about what was lost from settlement house workers and tenants.

As one resident told her: “Nobody cared what we wanted when they built this place. They threw our houses down and pushed us here and pushed our friends somewhere else. We don’t have a place around here to get a cup of coffee or a newspaper even... But the big men come and look at that grass and say, ‘Isn’t it wonderful! Now the poor have everything.’”

In varying ways, Jacobs celebrated the diversity of uses now witnessed in reviving cities; but she distinguished it from the congestion that comes with excessive single-use development.

Perhaps most relevant to the controversies engulfing today’s reviving cities is her warning about “cataclysmic money,” the kind that brings excessively tall towers for the super wealthy, foreign and domestic, along with tax and zoning policies that favor tourists over tax-paying residents. The “steady but gradual change” that “retains staying power after its novelty has gone,” she wrote in Death and Life, “requires a myriad of gradual, constant, close-grained changes.” That close-grain is exactly what’s missing from the over-celebrated and overwhelming encouragement of more and more tourists.

Rarely recognized, this is the negative side of accelerated change and it spells trouble for many cities—especially hyper-popular destinations like New York, New Orleans, San Francisco. These cities ignore the wisdom of Jacobs at their peril. Not today or tomorrow, maybe not for years to come, their downfall is inevitable and it will be painful, unless they wake up to the urban dynamics that Jacobs chronicled and analyzed half a century ago.

One thing is certain: If you do it for the local, the visitor will come; if you do it for the visitor, you will lose the local and, eventually, the visitor because it is the local who gives a place character. Read Jacobs to fully understand.